1. Field of the Invention
The present invention relates to sewing machines having one or more sewing heads, each sewing head having a plurality of needle bars. More particularly, the present invention relates to sewing machines in which operating parameters or conditions for each of the needle bars can be individually set.
2. Description of the Related Art
Known multi-needle sewing machines have a sewing head with a plurality of needle bars. Threads having different characteristics (such as color, thickness, smoothness and/or elasticity) are set on each of the respective needle bars. The operator can select any one of the needle bars to be driven, so that the sewing operation can be performed using the different kinds of threads. As a result, embroidery products can be automatically stitched with variations in color, thickness and/or texture.
In general, this type of sewing machine is designed such that the operator can set various operating conditions or parameters before the sewing operation is initiated. Such operating conditions may include, for example, xe2x80x9cthread cutting length,xe2x80x9d xe2x80x9cnumber of inching times,xe2x80x9d and xe2x80x9caccuracy in detection of thread cut threads.xe2x80x9d In this specification, the term xe2x80x9cthread cutting lengthxe2x80x9d means the length of the upper thread that extends from the needle bar after the upper thread has been intentionally cut by the sewing machine. The term xe2x80x9cnumber of inching timesxe2x80x9d means the number of times that the needle bar is reciprocated at a speed that is less than the normal sewing operation speed. An xe2x80x9cinchingxe2x80x9d operation is usually performed after the thread has been cut and a sewing operation is initiated with a new thread. In order to minimize the possibility that the thread will pull out of the fabric, the needle bar is first reciprocated at a slow speed when the sewing machine begins to stitch with the new thread in order to set the thread in the fabric. After a predetermined number of slow stitches (i.e. predetermined number of xe2x80x9cinching timesxe2x80x9d), the needle bar begins to reciprocate at the normal operating speed in order to complete the embroidery operation.
Known multi-needle sewing machines have been designed such that operating conditions or parameters can only be commonly set for all the needle bars of the sewing head. As a result, it is not possible to individually adjust the sewing operation in response to differing characteristics of the threads that are set on each of the needle bars.
It is, accordingly, one object of the present invention to teach improved sewing machines, in which the sewing operation can be suitably adjusted in response to differing characteristics of the threads that are set on the needle bars.
According to the present teachings, improved sewing machines are taught in which operating conditions or parameters can be individually set for different needle bars on the same sewing head. Thus, a first needle bar can operate using a first set operating conditions or parameters and a second needle bar on the same sewing head can operate using a second set of operating conditions or parameters.
In addition, sewing machines are taught in which the operating conditions or parameters can be individually set for each of the respective needle bars on a sewing head, or the same operating conditions or parameters can be utilized for all the needle bars on the sewing head. Preferably, the operating condition can be set by selecting either a common setting mode for setting the same operating conditions for all the needle bars or an individual setting mode for setting different operating conditions for the respective needle bars.
Other objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.